In conventional engine designs, it is quite common to employ a cooling system wherein a cooling medium, such as water or other suitable cooling agent, is circulated throughout the various components of an engine to dissipate the heat that is generated by the operation of an engine. More particularly, the engine block defines strategically positioned cavities or water jackets through which a flow of coolant is allowed to circulate. The coolant is normally circulated between the engine block and a radiator by an engine driven pump to dissipate heat that is created within the engine block. One main source of heat stems from the movement of the pistons within the cylinders and the combustion that creates such movement.
While this method of cooling has been known to be very effective for cooling the areas around the cylinders of a conventional engine block, it must be noted that this particular method of cooling relates only to the stationary portions of an engine block. It does not address a means by which the reciprocating members of an engine may be specifically cooled.
There are however, known methods used to cool the pistons of an engine. One such method is disclosed in U.S. Pat. No. 3,485,143, issued to Arthur R. Canady on Dec. 23, 1969. The Canady patent discloses the use of a sealed cavity in the upper region of the piston where the heat is known to be excessive. The cavity is filled with a cooling agent that acts as a heat exchanger to cool the crown portion of the piston as it reciprocates within its cylinder. This cooling arrangement however, applies only to a design that utilizes a piston assembly that is housed for reciprocation within a stationary cylinder.
In other engine designs having more advanced technology, piston arrangements are disclosed that utilize multiple piston arrangements that reciprocate with respect to one another. One such concept is disclosed in U.S. Pat. No. 3,630,178, issued to Frederick I. Erickson on Dec. 28, 1971. This patent discloses a primary or working piston that is moveable within a secondary combustion chamber member. The secondary combustion chamber member is in turn mounted for reciprocation within a cylinder formed by a stationary housing. It is apparent from a review of the disclosure that the combustion and expansion of gases within the interacting piston and moveable chamber would naturally create a substantial amount of heat in both moving members. While there are passages provided in the block of the engine through which water may be circulated to provide cooling of the block, there is no provision for cooling either of the moveable pistons.
The present invention is directed to overcoming one or more of the problems as set forth above.